Brodhead Pietenpol Association

I am starting to work out the fuel lines and someone, somewhere told me some do's and don'ts..... Of course I forgot them.

So what should I avoid when running the fuel line?

Dave

My Piet has the fuel tank up in the nose, so I can't speak authoritatively on this subject. However, from what I have read of William Wynne's writing about his experience when his Piet went down and fuel spilled out of the fuel lines from the tank in the centersection and went all over both cockpits and caught fire, there were some important lessons to be learned there. William was severely burned as he crawled away from the wreckage with his fuel-soaked clothing on fire. One of those things he emphasizes is that once the wing geometry is set (assuming you're building a Pietenpol and not a Grega, which does not have any way to adjust the wing cabane slant), the angled braces that go up to the forward cabanes to hold the wing in position should be robust and should be welded in place. If the wing shifts in a crash, the fuel lines leading down from the overhead tank will get crimped or break loose and will release fuel without any way to shut it off.

What I CAN speak authoritatively about because it happened to my plane is that in a nose-over, if the plane has the usual ball-joint ends on the cabane braces to permit adjustment of the wing angle, those fittings can easily fail, permitting the wing to shift as the plane goes over. If the fuel lines from overhead are run in rigid tubing, they can kink, fold, and break when this happens. Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

Here's the William Wynn article: https://flycorvair.net/2013/12/19/piete ... d-cabanes/

The highlights:

In the photo, you can see the diagonal cabanes on my plane were 5/8″ diameter, with small adjustable ends. This is bad. The minimum size I would use is 7/8″ x .058″, and these need to be welded to the front verticals, not bolted, and really not bolted in with flattened ends like a 1960s swing set.

the fuel line need to be a real braided steel AN flex line (not a rubber hose) and it needed to be secured with light, weak, plastic zip ties and have some slack in the system.

John C

Perfect!
Thanks